a little sparse, as foliage goes, and the tree will try to heal that cavity, as it ages.

I found that they look better, in simple pots of brown in colour, but I normally have buds sprouting continuously and the green remains alive with contrast.If the bark is cracked and furrowed, you still have to go to the next stage of maturity, flaking.

I think 7 years is too long for this stage.This is the problem when we forced the tree in a small pot at the early stage, and immediately turned it into "bonsai". The development would be much quicker if it was planted in a bigger pot/container and regularly being repotted. If you just acquired the tamarind, you can consider changing the pot in a bigger one, chances are it is already over pot bound by now. The base/nebari will also get matured if the roots can grow more freely, the branches can grow thicker too.